Friction reducing in flowing hydrocarbon fluids

ABSTRACT

THIS DISCLOSURE IS DIRECTED TO A METHOD AND COMPOSITION USEFUL IN REDUCING THE FRICTION LOSS IN FLOWING HYDROCARBON FLUIDS. THE COMPOSITION IS AN EMULSION CONSISTING ESSENTIALLY OF A HOMOPOLYMER OR COPOLYMER OF   R1-C(=CH)-CO-O-R2   WHERE R1 IS H OR CH3 AND R2 IS AN ALKYL GROUP OF 8 TO 18 CARBON ATOMS, A GLYCOL AND WATER. THE METHOD COMPRISES MIXING THE EMULSION WITH THE HYDROCARBON FLUID AND THEN ADDING A LOWER ALKYL ALCOHOL WHICH CAUSES THE POLYMER TO BE TRANSFERRED FROM THE EMULSION PHASE TO A HYDROCARBON SOLUTION.

United States Patent Ofiice 3,779,969 Patented Dec. 18, 1973 U.S. Cl.260-29.6 E Claims ABSTRACT OF THE DISCLOSURE This disclosure is directedto a method and composition useful in reducing the friction loss inflowing hydrocarbon fluids. The composition is an emulsion consistingessentially of a homopolymer or copolymer of where R is H or CH and R isan alkyl group of 8 to 18 carbon atoms, a glycol and water. The methodcomprises mixing the emulsion with the hydrocarbon fluid and then addinga lower alkyl alcohol which causes the polymer to be transferred fromthe emulsion phase to a hydrocarbon solution.

This is a division of application Serial No. 61,852, filed Aug. 6, 1970,now U.S. Pat. No. 3,654,994.

BACKGROUND OF THE INVENTION This invention relates to reducing frictionloss in flowing hydrocarbon fluids. More particularly, it relates to amethod for reducing the friction loss of hydrocarbon fluids flowing in aconduit by adding to the hydrocarbon fluid a friction reducing additivecomprising an emulsion of a polymer of where R is H or CH and R is analkyl group of 8 to 18 carbon atoms, a glycol and water.

In the process of transferring liquids in conduits, the problem of highfriction loss caused by nonlaminar flow is often encountered. Thisfrictional loss is especially great when the fluid is pumped under highpressures and at high velocities. In order to compensate for thisfriction loss, a considerable amount of energy must be expended inmoving the fluids.

The two most common industrial operations in which friction loss is amajor problem are oil well fracturing and the transmission of oil forconsiderable distance in petroleum pipelines. It is obvious that areduction in friction loss would permit lower surface operatingpressures, reduced power requirements and greater pressure at the bottomof the well bore in a fracturing operation and also increased flow ratesand reduced power requirements in the transmission process. Thus, it canreadily be seen that the reduction of friction in flowing hydrocarbonfluids is greatly desired.

In the past, various materials have been proposed and used as frictionreducers in hydrocarbon fluids. For example, see U.S. Pat. 3,288,577which discloses the use of certain high molecular weight polymers asfriction reducers. See also U.S. Pat. 3,351,079 which discloses the useof ethylene propylene copolymers and U.S. Pat. 3,215,- 154 whichdiscloses the use of polyisobutylene. Finally, see U.S. Pat. 3,493,000which discloses the use of polydimethylsiloxane as a friction reducer inhydrocarbon fluids.

Recently, it has been found that certain polyacrylates and methacrylatesare excellent friction reducers in hydrocarbon fluids. However, thesolubility rate of these polymers in crude oil is slow and in order touse the polymer readily, it must be predissolved in oil, kerosene or thelike. In addition, the polymers are usually prepared as aqueousemulsions and it has heretofore 'been necessary to recover the polymersfrom the emulsions before adding them to the oil or kerosene. Theseadditional steps of recovering the polymer and dissolving it increasethe cost of using the polymer. It would therefore be desirous to be ableto use the polyacrylate and polymethacrylate emulsions directly withouthaving to recover them and then dissolve them. However, the aqueousemulsions of the polymers do not have temperature stability at the lowtemperatures which are often encountered in the oil field processesespecially those temperatures encountered in the winter months in Alaskaand other areas. Therefore, even if the emulsion can be used directly,it is desirous that it have temperature stability.

SUMMARY OF THE INVENTION We have found a method of utilizing an emulsionof a polyacrylate or polymethacrylate to reduce friction in flowinghydrocarbons without having to isolate the polymer from the emulsion. Inaddition, we have found an emulsion which has goodtemperature stability.

The emulsion of our invention comprises (a) from 20 to about 60 percentby weight of a polymer of where R is H or CH and R is an alkyl group of8 to 18 carbon atoms, (b) from 10 to 50 percent by weight glycol, (c)from 10 to 60 percent by weight water, and (d) from 1 to 10 percent byweight emulsifying agent (surfactant). The preferred emulsion of ourinvention comprises (a) from 25 to 50 percent by weight of a polymer ofwhere R is H or CH, and R is an alkyl group of 8 to 18 carbon atoms, (b)from 15 to 40 percent by weight glycol, (c) from 20 to 50 percent byweight water, and (d) from 1 to 5 percent by weight emulsifying agent.

The useful glycols of our invention include ethylene glycol, propyleneglycol, diethylene glycol and the like. The preferred glycol is ethyleneglycol.

The polymer may be a homopolymer of the acrylate or methacrylate or itmay be a copolymer of the acrylate or methacrylate and up to 10 percentby weight of one or more suitable comonomers. Some of the suitablecomonomers are the lower alkyl acrylates and methacrylates such asmethylmethacrylate, ethyl acrylate, butyl acrylate and the like. Othersuitable comonomers include the dialkyl diallyl ammonium chlorides suchas dimethyl diallyl ammonium chloride, acrylamide and the N-substitutedacrylamides such as diacetone acrylamide. The comonomer is used toimpart various desirable properties to the final polymer. For example,the use of dimethyl diallyl ammonium chloride as the comonomer imparts aslight cationic charge to the final polymer and the use of acrylamidesprovide sites for hydrogen bonding, either of which gives the polymer ahydrophilic property. This property is desirable since the presence ofhydrophilic sites on the polymer will enhance the performance of thepolymer in hydrocarbon fluids containing small amounts of polarmaterials such as water, alcohols, thiols and the like.

The preferred polymer of our invention is polyisodecylmethacrylate.Therefore, when using the preferred polymer, the emulsion of ourinvention comprises (a) from 20 to about 60 percent by weightpolyisodecylmethacrylate, (b) from to 50 percent by weight glycol, (c)from 10 to 60 percent by weight water, and (d) from 1 to 10 percent byweight emulsifying agent (surfactant). Similarly, the preferred emulsionof our invention comprises (a) from 25 to 50 percent by weightpolyisodecylmethacrylate, (b) from to 40 percent by Weight glycol, (c)from to 50 percent by weight water, and (d) from 1 to 5 percent byweight emulsifying agent.

The emulsion of our invention may be prepared by polymerizing theacrylate or methacrylate monomer in an aqueous emulsion and then addingthe glycol or the emulsion may be prepared by polymerizing the acrylateor methacrylate in a cosolvent system of the glycol and water. The useof the cosolvent system is the preferred method. The use of thecosolvent system lowers the raw material cost, increases the yield ofpolymer and, in general, facilitates the polymerization process. Inaddition, we have found that by emulsion polymerizing the monomer in thecosolvent system of water and glycol the resulting polymer gives betterfriction reduction than a polymer prepared via an aqueous emulsion.

As mentioned above, the polymer of our invention is prepared by anemulsion polymerization technique. In the emulsion polymerization, thewater-insoluble monomer is emulsified in water or the water/ glycolcosolvent system by means of a surfactant. A polymerization initiator isadded and the polymer is formed. The polymeric emulsion must then remainin a homogeneous state. There must be no evidence of a phase separationeven when subjected to freeze-thaw temperature cycles ranging from about-30 F. to about 90 F. The polymeric emulsions of our invention havethese desired properties.

When polymerizing the acrylates and methacrylates of our invention inthe cosolvent system or in plain water, it is possible to use eithercationic, nonionic, anionic or amphoteric surfactants or a combinationof different surfactants. We have made emulsions using all types ofsurfactants. However, we have found that anionic surfactants such asdioctyl sodium sulfosuccinate give the most stable emulsions, which arenearly free from coagulum. We have also found that many differentpolymerization initiators may be used in preparing the emulsions of ourinvention. Examples of some of the useful initiators are ammoniumpersulfate, potassium persulfate, azobisisobutyronitrile, tertiary butylperoxypivalate, ter-e tiary butylperoxide, benzoyl peroxide and thelike. The preferred initiator of our invention is potassium persulfate.

The following examples illustrate the preparation and composition of theemulsions of our invention.

EXAMPLE 1 Into a one liter, four-necked flask equipped with stirrer,thermometer, reflux condenser and gas inlet tube was charged 200.0 gramsof isodecylmethacrylate, 162.0 grams of ethylene glycol and 162.0 gramsof water. The reaction mixture was purged with nitrogen for one andone-half hours. Then 16.8 grams of Triton GR-S (dioctyl sodiumsulfosuccinate) was added to the mixture. The temperature was increasedto 60 C. and 0.06 gram of potassium persulfate was added. The reactionmixture exothermed to 70 C. over a period of twenty minutes. Thereaction was then allowed to proceed for three hours at a temperaturebetween 60 and 70 C. The emulsion was placed in an atmosphere controlledat 30 F. for twenty-four hours. It was then allowed to stand at roomtemperature (-70" F.) for twenty-four hours. This cycle was repeatedthree times. The emulsion remained as a liquid with no phase separationnor formation of coagulum. This emulsion gave 64 percent frictionreduction in a hydrocarbon fluid as compared to polyisobutylene whichgave about 36 perecent.

EXAMPLE 2 Into a one liter, four-necked flask equipped with stirrer,thermometer, reflux condenser and gas inlet tube was charged 200.0 gramsof tridecylmethacrylate 162.0 grams of ethylene glycol and 162.0 gramsof water. The reaction mixture was purged with nitrogen for one andone-half hours. Then 16.8 grams of Triton GR-S (dioctyl sodiumsulfosuccinate) was added to the mixture. The temperature was increasedto 60 C. and 0.06 gram of potassium persulfate was added. The reactionmixture exothermed to 70 C. over a period of twenty minutes. Thereaction was then allowed to proceed for three hours at a temperaturebetween 60 and 70 C. The emulsion was placed in an atmosphere controlledat ---30 F. for twenty-four hours. It was then allowed to stand at roomtemperature (-70" F.) for twenty-four hours. This cycle was repeatedthree times. The emulsion remained as a liquid with no phase separationnor formation of coagulum. This emulsion showed friction reductionproperties of the same order of magnitude as polyisobutylene when testedin a hydrocarbon fluid.

EXAMPLE 3 Into a 250 ml., four-necked flask equipped with a stirrer,thermometer, reflux condenser and gas inlet tube was charged 50 grams ofisodecylmethacrylate, grams of water, and 2.5 grams of surfactant(sodium lauryl sulfate). The reaction mixture was then purged for onehour with argon. The temperature was increased to 60 C. and 0.015 gramof potassium persulfate was added. The reaction was then allowed toproceed for three hours at a temperature between 60 and 70 C. Thereaction mixture was cooled to room temperature and ethylene glycoladded so that the resulting mixture was 28.6 percent by weight ethyleneglycol. The emulsion was then placed in a freezer at 5 C. for sixteenhours. The emulsion remained as a liquid with no phase separation norformation of coagulum. This emulsion gave 60 percent friction reduction.

EXAMPLE 4 In a 250 ml. flask equipped with a stirrer, thermometer,reflux condenser and gas inlet tube was charged 40 gramsisodecylmethacrylate, 22 grams ehylene glycol, 38 grams water and 2grams sodium lauryl sulfate. The reaction mixture was then purged forone hour with argon and heated to 60 C. Then 0.012 gram potassiumpersulfate was added and the reaction allowed to proceed for three hoursat a temperature between 60 and 70 C. The emulsion was then subject to afreeze-thaw cycle ranging from -20 C. to room temperature. The emulsionwas stable with no phase separation nor coagulum. This emulsion gave 59percent friction reduction.

EXAMPLE 5 Into a 250 ml., four-necked flask equipped with a stirrer,thermometer, reflux condenser and gas inlet tube was charged 50 grams ofisodecylmethacrylate, 33 grams of ethylene glycol, 30 grams water and2.5 grams Triton GR-S. The reaction mixture was purged for one hour withnitrogen and heated to 60 C. Then 0.015 gram of potassium persulfate wasadded and the reaction allowed to proceed for three hours at 60 to 70 C.The resulting emulsion was stable and had no coagulum. The emulsion gavea friction reduction of 60.4 percent and was stable to temperature below16 C.

I EXAMPLE 6 Into a 250 ml., four-necked flask equipped with a stirrer,thermometer, reflux condenser and gas inlet tube was charged 50 gramsisodecylmethacrylate, 41 grams ethylene glycol, 62 grams water and 2.5grams Triton GR-S. The reaction mixture was purged for one hour withnitrogen and heated to 60 C. Then 0.015 grams of potassium persulfatewas added and the reaction allowed to proceed for three hours at 60 to70 C. The resulting emulsion was stable and had no coagulum. Theemulsion gave a friction reduction of 55.5 percent and was stable totemperatures below -9 C.

EXAMPLE 7 Into a. 25 0 ml, four-necked flask equipped with a stirrer,thermometer, reflux condenser and gas inlet tube was charged 50 gramsisodecylmethacrylate, 56.5 grams ethylene glycol, 46.5 grams water and2.5 grams Triton GR-S. The reaction mixture was purged for one hour withnitrogen and heated to 60 C. Then 0.015 gram potassium persulfate wasadded and the reaction allowed to proceed for three hours at 60 to 70 C.The result was a stable emulsion which had a small amount of coagulum.This emulsion was stable at temperatures below 43 F.

EXAMPLE 8 Into a one liter, four-necked flask equipped with a stirrer,thermometer, reflux condenser and gas inlet tube was charged 200 gramsof isodecylmethacrylate, 162 grams ethylene glycol, 162 grams water andgrams of Triton GR-S. The reaction mixture was purged for one hour withnitrogen and heated to 60 C. Then 0.06 gram of potassium persulfate wasadded and the reaction allowed to proceed for three hours. The resultingemulsion was stable and had no coagulum. The emulsion was then subjectedto three twenty-four hour free-thaw cycles ranging from 30 to +70 F. Theemulsion remained stable during these freeze-thaw cycles and gave afriction reduction of 65 percent.

EXAMPLE 9 Into a large reactor fitted With a stirrer, thermometer,reflux condenser and a gas inlet tube was charged 70.35 pounds ofisodecylmethacrylate, 56.27 pounds ethylene glycol, 56.27 poundsdistilled and 0.018 pound of sodium ethylene diamine tetraacetic acid.The reaction mixture was purged with nitrogen for one and one-half hoursand heated to 60 C. Then 0.018 pound of potassium persulfate was addedand the reaction allowed to proceed for five hours at a temperaturebetween 60 and 70 C. The result was a stable emulsion with no coagulum.The emulsion gave a friction reduction of 65 percent.

EXAMPLE 10 Into a one liter, four-necked flask equipped with a stirrer,thermomoeter, reflux condenser and gas inlet tube was charged 190 gramsof isodecylmethacrylate, 10 grams of dimethyl diallyl ammonium chloride,2.5 grams of Triton X-305 (a nonionic surfactant), 7.5 grams of Alacsan(a cationic surfactant), and 465 grams of water. The reaction mixturewas then purged with nitrogen for one and one-half hours and thetemperature raised to 60 C. Then 0.06 gram of potassium persulfate wasadded and the polymerization allowed to proceed for three hours at atemperature of about 75 C. The reaction mixture was then cooled to roomtemperature and the ethylene glycol was added so that the resultingpolymer emulsion was about 30 percent by weight glycol. This emulsionwas then subjected to a freeze-thaw test. The test was three cyclesranging from a temperature of 30 F. to +70 F. The emulsion was verystable and there was no phase separation at the end of the freeze-thawtest. This emulsion gave a friction reduction of 69 percent as comparedto 36 percent for polyisobutylene and 64 percent forpolyisodecylmethacrylate.

6 EXAMPLE 11 Into a one liter, four-necked flask equipped with astirrer, thermometer, reflux condenser, and gas inlet tube was charged190 grams of isodecylmethacrylate, 10 grams of diacetone acrylamide, 10grams of sodium lauryl sulfate, and 440 grams of water. The reactionmixture was then purged with nitrogen for one and one-half hours and thetemperature raised to 60 C. Then 006 gram of potassium persulfate wasadded and the polymerization allowed to proceed for three hours at 75 C.The reaction mixture was then cooled to room temperature and ethyleneglycol was added so that the emulsion was about 30 percent by weightethylene glycol. This emulsion was stable after a three cyclefreeze-thaw test having temperatures ranging from 30 F. to +70 F. Thisemulsion gave 64 percent friction reduction.

In addition to the isodecylmethacrylate emulsions illustrated above, wehave also prepared emulsions of other acrylates and methacrylates in amanner similar to those described in Examples 1 to 11 above. Among thedifferent acrylates and methacrylates which have been found to be usefulin our invention and which we have used to prepare emulsions are: 2ethylhexyl acrylate, tridecyl methacrylate, lauryl acrylate, laurylmethacrylate, stearyl acrylate and stearyl methacrylate. The emulsionsof these compounds all give a friction reducing effect in hydrocarbonfluids.

The friction reduction properties of the emulsions of our invention weredetermined in a hydrocarbon fluid which was pumped from a containerthrough a standard section of pipe and back into the container. Thistype of equipment is called a friction loop. The pressure drop in thepipe is continually measured and recorded. The pressure drop refers tothe loss or drop in pressure due to the friction of the fluid flowingthrough a conduit at a given velocity. The loss is measured by thedifference in pressure between any two given points along the conduitdivided by the distance between two points. The friction reduction ismeasured in the change in pressure drop due to the use of an additive.It is the decrease in the pressure differential required to move thesame fluid through the same distance of the same pipe at the samevelocity. The percent friction reduction is expressed by the formulaAPu-APa where APu is the pressure drop per unit length of pipe caused bythe friction of the untreated base fluid and where APa is the pressuredrop per unit length of pipe caused by the friction of the base fluidwith additive. Thus, the higher the number, the more effective thefriction reducing characteristics of the emulsion.

There is no reason to believe that there is a minimum molecular weightwhich must be achieved by the polymer in order to show friction reducingproperties. A low molecular weight polymer will have a slight effectwhen compared to a high molecular weight polymer. However, for allpractical purposes, it may be said that the polymer should have amolecular weight of at least 1,000,000. Similarly, there is no reason tobelieve that there is a minimum quantity which must be used to achieve afriction reducing effect. A small amount will have a silght eflect. Butfor practical purposes a minimum of 50 p.p.m. based on total weight ofhydrocarbon fluid is necessary. The maximum amount used will largely bedetermined by economic considerations. However, concentrations greaterthan 1,000 p.p.m. will seldom, if ever, be used. In the majority ofcases, a concentration in the neighborhood of 200 to 500 p.p.m. willproduce a commercially significant effect. The friction reduction valuesfor the emulsions of our invention given in the examples were determinedat a concentration of 400 p.p.m. based on active polymer and totalweight of hydrocarbon fluid, which was kerosene.

We have also found an effective method of using the emulsions of ourinvention in hydrocarbon liquids without having to first isolate thepolymer from the emulsion. Our method comprises adding the emulsion andhydrocarbon fluid together then adding to this mixture an alcohol suchas isopropanol or methanol. The alcohol causes the polymer to betransferred from the aqueous phase to the hydrocarbon phase. Theemulsion may be an aqueous emulsion of polymer and water or it may be anemulsion of polymer in the water/ glycol cosolvent system. Our methodcan also be practiced by adding the polymer emulsion and ahydrocarbon/alcohol mixture together. In addition, our method may bepracticed by simultaneously adding together the polymer emulsion, thehydrocarbon fluid, and the alcohol. In practicing any one of the abovevariations of our method, it must be remembered that the time of addingthe alcohol is critical. The alcohol should not be added to the emulsionprior to the time when the emulsion and hydrocarbon fluid are mixed. Wehave also found that the weight ratio of alcohol to polymer is acritical factor in using the method of our invention. When adding thepolymer emulsion and hydrocarbon fluid together, it is necessary to keepthe ratio of alcohol to emulsion between 1:2 and 5:1. The ratio ofalcohol to emulsion determines the speed and efficiency of the transferof the polymer from the emulsion to the hydrocarbon fluid. The maximumratio may be increased to values greater than 5:1 without having anydeleterious effect on the invention. However, we have found that for allpractical purposes, no advantage is gained by using a higher ratio.Similarly, amounts smaller than the minimum ratio of 1:2 may be used.However, we have found that when these small amounts are used thetransfer process is slow and ineflicient. The preferred ratio of thealcohol to emulsion is from 1:1 to 4:1. The alcohols which may be usedin practicing our invention may be described as lower alkyl alcohols;that is, alkyl groups of from about 1 to 6 carbon atoms. Some examplesof these alcohols are methanol, ethanol, propanol, butanol, pentanol,hexanol, isopropanol, isobutanol, tertiary butanol, and the like. Thepreferred alcohols are methanol and isopropanol. We have also found thatacetone may be used in place of the alcohol and the term lower alkylalcohol as used herein includes acetone unless otherwise stated.

The ratio of emulsion to hydrocarbon fluid will depend upon the amountof polymer that is desired in the hydrocarbon fluid and theconcentration of polymer in the emulsion. For example, if it is desiredto have the hydrocarbon fluid contain 0.5 percent by weight polymer andthe emulsion contains 20 percent by weight polymer, then the weightratio of emulsion to hydrocarbon fluid would be 2.5 :99.5. Similarly, ifit is desirous to have a hydrocarbon fluid containing 10 percent byweight polymer and the emulsion is 40 percent by weight polymer, thenthe weight ratio of emulsion to hydrocarbon fluid would be 25:90.Finally, for example, if it is desirous to have a hydrocarbon fluidcontaining 10 percent by weight polymer and the emulsion containspercent by weight polymer, then the ratio of emulsion to hydrocarbonfluid would be 50:90.

The following examples illustrate the method of our invention.

EXAMPLE 12 Into One holding container was placed 100 grams of a 33percent by weight polyisodecylmethacrylate emulsion (100 ml.). Intoanother holding container was placed 383 grams of kerosene (480 ml.) and67 grams of isopropanol (86 ml.). The solutions were pumped from theholding container at a ratio of 5.6 ml. of the kerosene/isopropanolmixture to 1 ml. of the emulsion into a static mixer such as describedin United States Pats. 2,894,732; 3,051,452; 3,051,453; 3,182,965;3,195,865; 3,206,170. As the mixture passed through the static mixturethe polyisodecylmethacrylate was transferred from the aqueous phase tothe kerosene. The kerosene eflluent was a very viscous solutioncontaining about 8 percent by weight polyisodecylmethacrylate.

EXAMPLE 13 Using the procedure described in Example 3, an emulsion wasprepared comprising 400 grams of polyisodecylmethacrylate, 800 gramswater and 20 grams of sodium lauryl sulfate. Then 14.4 parts of theemulsion was placed in 250 parts of kerosene and 25 parts of isopropanolwas added. This mixture was stirred for several minutes with amechanical agitator. The polyisodecylmethacrylate was transferred fromthe aqueous phase to the kerosene and the result was a viscous kerosenesolution containing 0.2 percent by weight polymer.

EXAMPLE 14 An emulsion comprising 33 percent by weightpolyisodecylmethacrylate in the cosolvent of ethylene glycol and waterwas prepared in a manner similar to the one described in Example 1. Then9 parts of the emulsion were added to 250 parts of kerosene and then 20parts of isopropanol were added to the mixture. The mixture was stirredfor several minutes and the polyisodecylmethacrylate was transferredinto the kerosene. The result was a kerosene solution containing 0.12percent by weight polymer.

EXAMPLE 15 About 13 parts of an emulsion as in Example 1 were mixed with250 parts of kerosene. Then 40 parts of isopropanol were added and themixture agitated for several minutes. The result was a viscous kerosenesolution containing about 0.2 percent by weight polymer.

We claim:

1. A polymeric emulsion for reducing the frictional pressure loss inhydrocarbon fluids resulting from the flow of the hydrocarbon fluidsthrough a conduit comprising (a) from 20 to 60 percent by weight of apolymer of where R is H or CH and R is an alkyl group of 8 to 18 carbonatoms, wherein the polymer is a homopolymer or a copolymer of up to 10percent by weight of a comonomer selected from the group consisting ofdialkyl diallyl ammonium chlorides, lower alkyl acrylates andN-substituted acrylamides, (b) from 10 to 50 percent by weight of aglycol, selected from the group consisting of ethylene glycol, propyleneglycol and diethylene glycol, (c) from 10 to 60 percent by weight water,and (d) from 1 to 10 percent by weight surfactant.

2. A polymer emulsion as in claim 1 wherein the glycol is ethyleneglycol.

3. A polymer emulsion as in claim 1 wherein the polymer is a copolymer.

4. A polymer emulsion as in claim 3 wherein the comonomer is a dialkyldiallyl ammonium chloride.

5. A polymer emulsion as in claim 3 wherein the comonomer is anacrylamide.

6. A polymer emulsion for reducing the frictional pressure loss inhydrocarbon fluids resulting from the flow of the hydrocarbon fluidsthrough a conduit comprising (a) from 20 to 60 percent by weight of ahomoor copolymer of isodecylmethacrylate, wherein the copolymer containsup to 10 percent by weight of a comonomer selected from the groupconsisting of dialkyl diallyl ammonium chloride, lower alkyl acrylatesand N-substituted acrylamides, (b) from 10 to 50 percent by Weight of aglycol selected from the group consisting of ethylene glycol, propyleneglycol and diethylene glycol, (c) from 10 to 60 percent by weight water,and (d) from 1 to 10 percent by weight surfactant.

7. A polymer emulsion as in claim 6 wherein the glycol is ethyleneglycol.

8. A polymer emulsion as in claim 6 wherein the polymer is a copolyrner.

9. A polymer emulsion as in claim 8 wherein the comonomer is a dialkyldiallyl ammonium chloride.

No references cited.

MELVIN GOLDSTEIN, Primary Examiner US. Cl. X.R.

260-296 ME, 33.6 VA

